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94-552: The dam was built between 1950 and 1960 and is used to generate hydroelectricity at the Bicaz-Stejaru Hydroelectric Power Station . It has a height of 127 m (417 ft), a length of 435 m (1,427 ft), and a maximum width of 119 m (390 ft). It is a gravity dam made of concrete and connects Mount Gicovanu with Obcina Horștei, located upstream of the confluence of the stream Izvorul Muntelui with Bistrița. Geologically it

188-745: A greenhouse gas . According to the World Commission on Dams report, where the reservoir is large compared to the generating capacity (less than 100 watts per square metre of surface area) and no clearing of the forests in the area was undertaken prior to impoundment of the reservoir, greenhouse gas emissions from the reservoir may be higher than those of a conventional oil-fired thermal generation plant. In boreal reservoirs of Canada and Northern Europe, however, greenhouse gas emissions are typically only 2% to 8% of any kind of conventional fossil-fuel thermal generation. A new class of underwater logging operation that targets drowned forests can mitigate

282-463: A low-head hydro power plant with hydrostatic head of few meters to few tens of meters can be classified either as an SHP or an LHP. The other distinction between SHP and LHP is the degree of the water flow regulation: a typical SHP primarily uses the natural water discharge with very little regulation in comparison to an LHP. Therefore, the term SHP is frequently used as a synonym for the run-of-the-river power plant . The largest power producers in

376-421: A flood and fail. Changes in the amount of river flow will correlate with the amount of energy produced by a dam. Lower river flows will reduce the amount of live storage in a reservoir therefore reducing the amount of water that can be used for hydroelectricity. The result of diminished river flow can be power shortages in areas that depend heavily on hydroelectric power. The risk of flow shortage may increase as

470-411: A given year to that year's total emissions. The annual airborne fraction for CO 2 had been stable at 0.45 for the past six decades even as the emissions have been increasing. This means that the other 0.55 of emitted CO 2 is absorbed by the land and atmosphere carbon sinks within the first year of an emission. In the high-emission scenarios, the effectiveness of carbon sinks will be lower, increasing

564-400: A greenhouse gas would absorb over a given time frame after it has been added to the atmosphere (or emitted to the atmosphere). The GWP makes different greenhouse gases comparable with regard to their "effectiveness in causing radiative forcing ". It is expressed as a multiple of the radiation that would be absorbed by the same mass of added carbon dioxide (CO 2 ), which is taken as

658-494: A hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel -powered energy plants. However, when constructed in lowland rainforest areas, where part of the forest is inundated, substantial amounts of greenhouse gases may be emitted. Construction of a hydroelectric complex can have significant environmental impact, principally in loss of arable land and population displacement. They also disrupt

752-809: A large natural height difference between two waterways, such as a waterfall or mountain lake. A tunnel is constructed to take water from the high reservoir to the generating hall built in a cavern near the lowest point of the water tunnel and a horizontal tailrace taking water away to the lower outlet waterway. A simple formula for approximating electric power production at a hydroelectric station is: P = − η   ( m ˙ g   Δ h ) = − η   ( ( ρ V ˙ )   g   Δ h ) {\displaystyle P=-\eta \ ({\dot {m}}g\ \Delta h)=-\eta \ ((\rho {\dot {V}})\ g\ \Delta h)} where Efficiency

846-451: A larger amount of methane than those in temperate areas. Like other non-fossil fuel sources, hydropower also has no emissions of sulfur dioxide, nitrogen oxides, or other particulates. Reservoirs created by hydroelectric schemes often provide facilities for water sports , and become tourist attractions themselves. In some countries, aquaculture in reservoirs is common. Multi-use dams installed for irrigation support agriculture with

940-539: A molecule of X remains in the box. τ {\displaystyle \tau } can also be defined as the ratio of the mass m {\displaystyle m} (in kg) of X in the box to its removal rate, which is the sum of the flow of X out of the box ( F out {\displaystyle F_{\text{out}}} ), chemical loss of X ( L {\displaystyle L} ), and deposition of X ( D {\displaystyle D} ) (all in kg/s): If input of this gas into

1034-414: A much shorter atmospheric lifetime than carbon dioxide, its GWP is much less over longer time periods, with a GWP-100 of 27.9 and a GWP-500 of 7.95. The contribution of each gas to the enhanced greenhouse effect is determined by the characteristics of that gas, its abundance, and any indirect effects it may cause. For example, the direct radiative effect of a mass of methane is about 84 times stronger than

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1128-592: A positive risk adjusted return, unless appropriate risk management measures are put in place. While many hydroelectric projects supply public electricity networks, some are created to serve specific industrial enterprises. Dedicated hydroelectric projects are often built to provide the substantial amounts of electricity needed for aluminium electrolytic plants, for example. The Grand Coulee Dam switched to support Alcoa aluminium in Bellingham, Washington , United States for American World War II airplanes before it

1222-445: A process known as water vapor feedback. It occurs because Clausius–Clapeyron relation establishes that more water vapor will be present per unit volume at elevated temperatures. Thus, local atmospheric concentration of water vapor varies from less than 0.01% in extremely cold regions and up to 3% by mass in saturated air at about 32 °C. Global warming potential (GWP) is an index to measure how much infrared thermal radiation

1316-503: A reference gas. Therefore, the GWP has a value of 1 for CO 2 . For other gases it depends on how strongly the gas absorbs infrared thermal radiation, how quickly the gas leaves the atmosphere, and the time frame being considered. For example, methane has a GWP over 20 years (GWP-20) of 81.2 meaning that, for example, a leak of a tonne of methane is equivalent to emitting 81.2 tonnes of carbon dioxide measured over 20 years. As methane has

1410-548: A relatively constant water supply. Large hydro dams can control floods, which would otherwise affect people living downstream of the project. Managing dams which are also used for other purposes, such as irrigation , is complicated. In 2021 the IEA called for "robust sustainability standards for all hydropower development with streamlined rules and regulations". Large reservoirs associated with traditional hydroelectric power stations result in submersion of extensive areas upstream of

1504-540: A result of climate change . One study from the Colorado River in the United States suggest that modest climate changes, such as an increase in temperature in 2 degree Celsius resulting in a 10% decline in precipitation, might reduce river run-off by up to 40%. Brazil in particular is vulnerable due to its heavy reliance on hydroelectricity, as increasing temperatures, lower water flow and alterations in

1598-408: A single number. Scientists instead say that while the first 10% of carbon dioxide's airborne fraction (not counting the ~50% absorbed by land and ocean sinks within the emission's first year) is removed "quickly", the vast majority of the airborne fraction – 80% – lasts for "centuries to millennia". The remaining 10% stays for tens of thousands of years. In some models, this longest-lasting fraction

1692-448: A small TV/radio). Even smaller turbines of 200–300 W may power a few homes in a developing country with a drop of only 1 m (3 ft). A Pico-hydro setup is typically run-of-the-river , meaning that dams are not used, but rather pipes divert some of the flow, drop this down a gradient, and through the turbine before returning it to the stream. An underground power station is generally used at large facilities and makes use of

1786-456: A small submersible used for underwater exploration. The facility was visited by the marine biologist Jacques-Yves Cousteau in 1984. This Neamț County location article is a stub . You can help Misplaced Pages by expanding it . Hydroelectricity Hydroelectricity , or hydroelectric power , is electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity , almost 4,210 TWh in 2023, which

1880-455: A source of low-cost renewable energy. Alternatively, small hydro projects may be built in isolated areas that would be uneconomic to serve from a grid, or in areas where there is no national electrical distribution network. Since small hydro projects usually have minimal reservoirs and civil construction work, they are seen as having a relatively low environmental impact compared to large hydro. This decreased environmental impact depends strongly on

1974-414: A start-up time of the order of a few minutes. Although battery power is quicker its capacity is tiny compared to hydro. It takes less than 10 minutes to bring most hydro units from cold start-up to full load; this is quicker than nuclear and almost all fossil fuel power. Power generation can also be decreased quickly when there is a surplus power generation. Hence the limited capacity of hydropower units

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2068-581: A total of 1,500 terawatt-hours (TWh) of electrical energy in one full cycle" which was "about 170 times more energy than the global fleet of pumped storage hydropower plants". Battery storage capacity is not expected to overtake pumped storage during the 2020s. When used as peak power to meet demand, hydroelectricity has a higher value than baseload power and a much higher value compared to intermittent energy sources such as wind and solar. Hydroelectric stations have long economic lives, with some plants still in service after 50–100 years. Operating labor cost

2162-491: A variety of Atmospheric Chemistry Observational Databases . The table below shows the most influential long-lived, well-mixed greenhouse gases, along with their tropospheric concentrations and direct radiative forcings , as identified by the Intergovernmental Panel on Climate Change (IPCC). Abundances of these trace gases are regularly measured by atmospheric scientists from samples collected throughout

2256-453: A year's worth of rain fell within 24 hours (see 1975 Banqiao Dam failure ). The resulting flood resulted in the deaths of 26,000 people, and another 145,000 from epidemics. Millions were left homeless. The creation of a dam in a geologically inappropriate location may cause disasters such as 1963 disaster at Vajont Dam in Italy, where almost 2,000 people died. Greenhouse gas This

2350-452: Is hydroelectric power on a scale serving a small community or industrial plant. The definition of a small hydro project varies but a generating capacity of up to 10 megawatts (MW) is generally accepted as the upper limit. This may be stretched to 25 MW and 30 MW in Canada and the United States. Small hydro stations may be connected to conventional electrical distribution networks as

2444-478: Is a tourist destination in the region, especially in summertime, when visitors take the ferryboat from the Bicaz port for a short trip on the lake, and to view Mount Ceahlău on the west shore. In the 1960s and 1970s there was regular ferry service between the Bicaz port and the villages on the lake shore. At Potoci, a few kilometers north of the town of Bicaz, there is a biological research facility, equipped with

2538-520: Is a CO 2 molecule. The first 30 ppm increase in CO 2 concentrations took place in about 200 years, from the start of the Industrial Revolution to 1958; however the next 90 ppm increase took place within 56 years, from 1958 to 2014. Similarly, the average annual increase in the 1960s was only 37% of what it was in 2000 through 2007. Many observations are available online in

2632-535: Is a level which the Intergovernmental Panel on Climate Change (IPCC) says is "dangerous". Greenhouse gases are infrared active, meaning that they absorb and emit infrared radiation in the same long wavelength range as what is emitted by the Earth's surface, clouds and atmosphere. 99% of the Earth's dry atmosphere (excluding water vapor ) is made up of nitrogen ( N 2 ) (78%) and oxygen ( O 2 ) (21%). Because their molecules contain two atoms of

2726-434: Is also cooling the upper atmosphere, as it is much thinner than the lower layers, and any heat re-emitted from greenhouse gases is more likely to travel further to space than to interact with the fewer gas molecules in the upper layers. The upper atmosphere is also shrinking as the result. Anthropogenic changes to the natural greenhouse effect are sometimes referred to as the enhanced greenhouse effect . This table shows

2820-635: Is also usually low, as plants are automated and have few personnel on site during normal operation. Where a dam serves multiple purposes, a hydroelectric station may be added with relatively low construction cost, providing a useful revenue stream to offset the costs of dam operation. It has been calculated that the sale of electricity from the Three Gorges Dam will cover the construction costs after 5 to 8 years of full generation. However, some data shows that in most countries large hydropower dams will be too costly and take too long to build to deliver

2914-403: Is an accepted version of this page Greenhouse gases ( GHGs ) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. What distinguishes them from other gases is that they absorb the wavelengths of radiation that a planet emits , resulting in the greenhouse effect . The Earth is warmed by sunlight, causing its surface to radiate heat , which

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3008-489: Is an asymmetry in electric charge distribution which allows molecular vibrations to interact with electromagnetic radiation. This makes them infrared active, and so their presence causes greenhouse effect . Earth absorbs some of the radiant energy received from the sun, reflects some of it as light and reflects or radiates the rest back to space as heat . A planet's surface temperature depends on this balance between incoming and outgoing energy. When Earth's energy balance

3102-515: Is as large as 30%. Estimates in 2023 found that the current carbon dioxide concentration in the atmosphere may be the highest it has been in the last 14 million years. However the IPCC Sixth Assessment Report estimated similar levels 3 to 3.3 million years ago in the mid-Pliocene warm period . This period can be a proxy for likely climate outcomes with current levels of CO 2 . Greenhouse gas monitoring involves

3196-470: Is highest in the winter when solar energy is at a minimum. Pico hydro is hydroelectric power generation of under 5 kW . It is useful in small, remote communities that require only a small amount of electricity. For example, the 1.1 kW Intermediate Technology Development Group Pico Hydro Project in Kenya supplies 57 homes with very small electric loads (e.g., a couple of lights and a phone charger, or

3290-445: Is initially produced during construction of the project, and some methane is given off annually by reservoirs, hydro has one of the lowest lifecycle greenhouse gas emissions for electricity generation. The low greenhouse gas impact of hydroelectricity is found especially in temperate climates . Greater greenhouse gas emission impacts are found in the tropical regions because the reservoirs of power stations in tropical regions produce

3384-476: Is installed where the Izvorul Muntelui stream crosses the diversion gallery, with the stream flowing directly into the gallery. The water accumulated at Tașca is used both for electricity production in the "Bicaz-Stejaru" hydroelectric power plant and for supplying the cement factory in the locality or for other downstream needs. The hydroelectric power plant is located 15 km downstream from the dam, in

3478-530: Is located in an area with predominantly siliceous sandstones (Tarcău sandstone), the rest being packages of argillaceous shales and a layer of conglomerates. The foundation soil shows a strong cracking. Its structure consists of 30 high blocks (plots) separated by joints sealed upstream with reinforced concrete wedges and copper sheeting. It is crossed by galleries, ventilation shafts and manholes. The construction has provided rooms that house drive and control installations, equipment for seismic monitoring and tracking

3572-471: Is more than all other renewable sources combined and also more than nuclear power . Hydropower can provide large amounts of low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once

3666-403: Is mostly due to the rapid growth and cumulative magnitude of the disturbances to Earth's carbon cycle by the geologic extraction and burning of fossil carbon. As of year 2014, fossil CO 2 emitted as a theoretical 10 to 100 GtC pulse on top of the existing atmospheric concentration was expected to be 50% removed by land vegetation and ocean sinks in less than about a century, as based on

3760-462: Is not an energy source, and appears as a negative number in listings. Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that only the water coming from upstream is available for generation at that moment, and any oversupply must pass unused. A constant supply of water from a lake or existing reservoir upstream is a significant advantage in choosing sites for run-of-the-river. A tidal power station makes use of

3854-452: Is not generally used to produce base power except for vacating the flood pool or meeting downstream needs. Instead, it can serve as backup for non-hydro generators. The major advantage of conventional hydroelectric dams with reservoirs is their ability to store water at low cost for dispatch later as high value clean electricity. In 2021, the IEA estimated that the "reservoirs of all existing conventional hydropower plants combined can store

Lake Izvorul Muntelui - Misplaced Pages Continue

3948-410: Is often higher (that is, closer to 1) with larger and more modern turbines. Annual electric energy production depends on the available water supply. In some installations, the water flow rate can vary by a factor of 10:1 over the course of a year. Hydropower is a flexible source of electricity since stations can be ramped up and down very quickly to adapt to changing energy demands. Hydro turbines have

4042-507: Is shifted, its surface becomes warmer or cooler, leading to a variety of changes in global climate. Radiative forcing is a metric calculated in watts per square meter, which characterizes the impact of an external change in a factor that influences climate. It is calculated as the difference in top-of-atmosphere (TOA) energy balance immediately caused by such an external change. A positive forcing, such as from increased concentrations of greenhouse gases, means more energy arriving than leaving at

4136-489: Is the level the United Nations' Intergovernmental Panel on Climate Change (IPCC) says is "dangerous". Most greenhouse gases have both natural and human-caused sources. An exception are purely human-produced synthetic halocarbons which have no natural sources. During the pre-industrial Holocene , concentrations of existing gases were roughly constant, because the large natural sources and sinks roughly balanced. In

4230-499: Is the most important greenhouse gas overall, being responsible for 41–67% of the greenhouse effect, but its global concentrations are not directly affected by human activity. While local water vapor concentrations can be affected by developments such as irrigation , it has little impact on the global scale due to its short residence time of about nine days. Indirectly, an increase in global temperatures cause will also increase water vapor concentrations and thus their warming effect, in

4324-644: Is then mostly absorbed by greenhouse gases. Without greenhouse gases in the atmosphere, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F). The five most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order of average global mole fraction , are: water vapor , carbon dioxide , methane , nitrous oxide , ozone . Other greenhouse gases of concern include chlorofluorocarbons (CFCs and HCFCs ), hydrofluorocarbons (HFCs), perfluorocarbons , SF 6 , and NF 3 . Water vapor causes about half of

4418-679: The Bonneville Dam in 1937 and being recognized by the Flood Control Act of 1936 as the premier federal flood control agency. Hydroelectric power stations continued to become larger throughout the 20th century. Hydropower was referred to as "white coal". Hoover Dam 's initial 1,345 MW power station was the world's largest hydroelectric power station in 1936; it was eclipsed by the 6,809 MW Grand Coulee Dam in 1942. The Itaipu Dam opened in 1984 in South America as

4512-806: The International Exhibition of Hydropower and Tourism , with over one million visitors 1925. By 1920, when 40% of the power produced in the United States was hydroelectric, the Federal Power Act was enacted into law. The Act created the Federal Power Commission to regulate hydroelectric power stations on federal land and water. As the power stations became larger, their associated dams developed additional purposes, including flood control , irrigation and navigation . Federal funding became necessary for large-scale development, and federally owned corporations, such as

4606-633: The Tennessee Valley Authority (1933) and the Bonneville Power Administration (1937) were created. Additionally, the Bureau of Reclamation which had begun a series of western US irrigation projects in the early 20th century, was now constructing large hydroelectric projects such as the 1928 Hoover Dam . The United States Army Corps of Engineers was also involved in hydroelectric development, completing

4700-583: The Vulcan Street Plant , began operating September 30, 1882, in Appleton, Wisconsin , with an output of about 12.5 kilowatts. By 1886 there were 45 hydroelectric power stations in the United States and Canada; and by 1889 there were 200 in the United States alone. At the beginning of the 20th century, many small hydroelectric power stations were being constructed by commercial companies in mountains near metropolitan areas. Grenoble , France held

4794-526: The greenhouse effect is heavily driven by water vapor , human emissions of water vapor are not a significant contributor to warming. The annual "Emissions Gap Report" by UNEP stated in 2022 that it was necessary to almost halve emissions. "To get on track for limiting global warming to 1.5°C, global annual GHG emissions must be reduced by 45 per cent compared with emissions projections under policies currently in place in just eight years, and they must continue to decline rapidly after 2030, to avoid exhausting

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4888-506: The potential energy of dammed water driving a water turbine and generator . The power extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the head . A large pipe (the " penstock ") delivers water from the reservoir to the turbine. This method produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand,

4982-463: The IEA released a main-case forecast of 141 GW generated by hydropower over 2022–2027, which is slightly lower than deployment achieved from 2017–2022. Because environmental permitting and construction times are long, they estimate hydropower potential will remain limited, with only an additional 40 GW deemed possible in the accelerated case. In 2021 the IEA said that major modernisation refurbishments are required. Most hydroelectric power comes from

5076-464: The ability to transport particles heavier than itself downstream. This has a negative effect on dams and subsequently their power stations, particularly those on rivers or within catchment areas with high siltation. Siltation can fill a reservoir and reduce its capacity to control floods along with causing additional horizontal pressure on the upstream portion of the dam. Eventually, some reservoirs can become full of sediment and useless or over-top during

5170-469: The atmosphere into bodies of water (ocean, lakes, etc.), as well as dissolving in precipitation as raindrops fall through the atmosphere. When dissolved in water, carbon dioxide reacts with water molecules and forms carbonic acid , which contributes to ocean acidity . It can then be absorbed by rocks through weathering . It also can acidify other surfaces it touches or be washed into the ocean. The vast majority of carbon dioxide emissions by humans come from

5264-427: The atmosphere, terrestrial ecosystems , the ocean, and sediments . These flows have been fairly balanced over the past 1 million years, although greenhouse gas levels have varied widely in the more distant past . Carbon dioxide levels are now higher than they have been for 3 million years. If current emission rates continue then global warming will surpass 2.0 °C (3.6 °F) sometime between 2040 and 2070. This

5358-459: The atmospheric fraction of CO 2 even though the raw amount of emissions absorbed will be higher than in the present. Major greenhouse gases are well mixed and take many years to leave the atmosphere. The atmospheric lifetime of a greenhouse gas refers to the time required to restore equilibrium following a sudden increase or decrease in its concentration in the atmosphere. Individual atoms or molecules may be lost or deposited to sinks such as

5452-423: The balance between sources (emissions of the gas from human activities and natural systems) and sinks (the removal of the gas from the atmosphere by conversion to a different chemical compound or absorption by bodies of water). The proportion of an emission remaining in the atmosphere after a specified time is the " airborne fraction " (AF). The annual airborne fraction is the ratio of the atmospheric increase in

5546-595: The balance between stream flow and power production. Micro hydro means hydroelectric power installations that typically produce up to 100 kW of power. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without purchase of fuel. Micro hydro systems complement photovoltaic solar energy systems because in many areas water flow, and thus available hydro power,

5640-470: The behavior of each element. At the top, there are four 11.5 m wide spillway fields for a 7 m high water blade (equipped with 6 m segment staves) and four bottom clearings equipped with flat valves (2.50 m diameter) in glasses, arranged in series. The lake has a length of 40 km (25 mi), an area of 31 km (12 sq mi) and a maximum volume of 1,250 billion m³. It stretches from north-west to south-east, with frequent lateral expansion areas,

5734-502: The box ceased, then after time τ {\displaystyle \tau } , its concentration would decrease by about 63%. Changes to any of these variables can alter the atmospheric lifetime of a greenhouse gas. For instance, methane's atmospheric lifetime is estimated to have been lower in the 19th century than now, but to have been higher in the second half of the 20th century than after 2000. Carbon dioxide has an even more variable lifetime, which cannot be specified down to

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5828-401: The burning of fossil fuels , with remaining contributions from agriculture and industry . Methane emissions originate from agriculture, fossil fuel production, waste, and other sources. The carbon cycle takes thousands of years to fully absorb CO 2 from the atmosphere, while methane lasts in the atmosphere for an average of only 12 years. Natural flows of carbon happen between

5922-405: The burning of fossil fuels . Additional contributions come from cement manufacturing, fertilizer production, and changes in land use like deforestation . Methane emissions originate from agriculture , fossil fuel production, waste, and other sources. If current emission rates continue then temperature rises will surpass 2.0 °C (3.6 °F) sometime between 2040 and 2070, which

6016-404: The daily rise and fall of ocean water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatchable to generate power during high demand periods. Less common types of hydro schemes use water's kinetic energy or undammed sources such as undershot water wheels . Tidal power is viable in a relatively small number of locations around

6110-505: The dams, sometimes destroying biologically rich and productive lowland and riverine valley forests, marshland and grasslands. Damming interrupts the flow of rivers and can harm local ecosystems, and building large dams and reservoirs often involves displacing people and wildlife. The loss of land is often exacerbated by habitat fragmentation of surrounding areas caused by the reservoir. Hydroelectric projects can be disruptive to surrounding aquatic ecosystems both upstream and downstream of

6204-454: The direct measurement of atmospheric concentrations and direct and indirect measurement of greenhouse gas emissions . Indirect methods calculate emissions of greenhouse gases based on related metrics such as fossil fuel extraction. There are several different methods of measuring carbon dioxide concentrations in the atmosphere, including infrared analyzing and manometry . Methane and nitrous oxide are measured by other instruments, such as

6298-705: The effect of forest decay. Another disadvantage of hydroelectric dams is the need to relocate the people living where the reservoirs are planned. In 2000, the World Commission on Dams estimated that dams had physically displaced 40–80 million people worldwide. Because large conventional dammed-hydro facilities hold back large volumes of water, a failure due to poor construction, natural disasters or sabotage can be catastrophic to downriver settlements and infrastructure. During Typhoon Nina in 1975 Banqiao Dam in Southern China failed when more than

6392-399: The excess generation capacity is used to pump water into the higher reservoir, thus providing demand side response . When the demand becomes greater, water is released back into the lower reservoir through a turbine. In 2021 pumped-storage schemes provided almost 85% of the world's 190 GW of grid energy storage and improve the daily capacity factor of the generation system. Pumped storage

6486-446: The greenhouse effect, acting in response to other gases as a climate change feedback . Human activities since the beginning of the Industrial Revolution (around 1750) have increased carbon dioxide by over 50% , and methane levels by 150%. Carbon dioxide emissions are causing about three-quarters of global warming , while methane emissions cause most of the rest. The vast majority of carbon dioxide emissions by humans come from

6580-506: The industrial era, human activities have added greenhouse gases to the atmosphere, mainly through the burning of fossil fuels and clearing of forests. The major anthropogenic (human origin) sources of greenhouse gases are carbon dioxide (CO 2 ), nitrous oxide ( N 2 O ), methane and three groups of fluorinated gases ( sulfur hexafluoride ( SF 6 ), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs, sulphur hexafluoride (SF 6 ), and nitrogen trifluoride (NF 3 )). Though

6674-429: The largest amount for the region since 1990. Meanwhile, globally, hydropower generation increased by 70 TWh (up 2%) in 2022 and remains the largest renewable energy source, surpassing all other technologies combined. Hydropower has been used since ancient times to grind flour and perform other tasks. In the late 18th century hydraulic power provided the energy source needed for the start of the Industrial Revolution . In

6768-750: The largest, producing 14 GW , but was surpassed in 2008 by the Three Gorges Dam in China at 22.5 GW . Hydroelectricity would eventually supply some countries, including Norway , Democratic Republic of the Congo , Paraguay and Brazil , with over 85% of their electricity. In 2021 the International Energy Agency (IEA) said that more efforts are needed to help limit climate change . Some countries have highly developed their hydropower potential and have very little room for growth: Switzerland produces 88% of its potential and Mexico 80%. In 2022,

6862-616: The late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand arising from the Industrial Revolution would drive development as well. In 1878, the world's first hydroelectric power scheme was developed at Cragside in Northumberland , England, by William Armstrong . It was used to power a single arc lamp in his art gallery. The old Schoelkopf Power Station No. 1 , US, near Niagara Falls , began to produce electricity in 1881. The first Edison hydroelectric power station,

6956-455: The limited remaining atmospheric carbon budget ." The report commented that the world should focus on broad-based economy-wide transformations and not incremental change. Several technologies remove greenhouse gas emissions from the atmosphere. Most widely analyzed are those that remove carbon dioxide from the atmosphere, either to geologic formations such as bio-energy with carbon capture and storage and carbon dioxide air capture , or to

7050-488: The mid-1700s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique , which described vertical- and horizontal-axis hydraulic machines, and in 1771 Richard Arkwright 's combination of water power , the water frame , and continuous production played a significant part in the development of the factory system, with modern employment practices. In the 1840s, hydraulic power networks were developed to generate and transmit hydro power to end users. By

7144-828: The most important contributions to the overall greenhouse effect, without which the average temperature of Earth's surface would be about −18 °C (0 °F), instead of around 15 °C (59 °F). This table also specifies tropospheric ozone , because this gas has a cooling effect in the stratosphere , but a warming influence comparable to nitrous oxide and CFCs in the troposphere . K&T (1997) used 353 ppm CO 2 and calculated 125 W/m total clear-sky greenhouse effect; relied on single atmospheric profile and cloud model. "With Clouds" percentages are from Schmidt (2010) interpretation of K&T (1997). Schmidt (2010) used 1980 climatology with 339 ppm CO 2 and 155 W/m total greenhouse effect; accounted for temporal and 3-D spatial distribution of absorbers. Water vapor

7238-481: The most important of which is the one on the Bistricioara river (about 3 km). Two secondary reservoirs at Tașca and Izvoru Muntelui divert water from the Bicaz and Izvorul Muntelui rivers into the main lake. The Tașca reservoir is located behind a weir type dam with two spill fields equipped with 2 segment staves. The water inlet is continued by a bypass gallery providing the servitute discharge. The second intake

7332-651: The natural ecology of the river involved, affecting habitats and ecosystems, and siltation and erosion patterns. While dams can ameliorate the risks of flooding, dam failure can be catastrophic. In 2021, global installed hydropower electrical capacity reached almost 1,400 GW, the highest among all renewable energy technologies. Hydroelectricity plays a leading role in countries like Brazil, Norway and China. but there are geographical limits and environmental issues. Tidal power can be used in coastal regions. China added 24 GW in 2022, accounting for nearly three-quarters of global hydropower capacity additions. Europe added 2 GW,

7426-633: The plant site. Generation of hydroelectric power changes the downstream river environment. Water exiting a turbine usually contains very little suspended sediment, which can lead to scouring of river beds and loss of riverbanks. The turbines also will kill large portions of the fauna passing through, for instance 70% of the eel passing a turbine will perish immediately. Since turbine gates are often opened intermittently, rapid or even daily fluctuations in river flow are observed. Drought and seasonal changes in rainfall can severely limit hydropower. Water may also be lost by evaporation. When water flows it has

7520-508: The projections of coupled models referenced in the AR5 assessment. A substantial fraction (20–35%) was also projected to remain in the atmosphere for centuries to millennia, where fractional persistence increases with pulse size. Values are relative to year 1750. AR6 reports the effective radiative forcing which includes effects of rapid adjustments in the atmosphere and at the surface. Atmospheric concentrations are determined by

7614-450: The rainfall regime, could reduce total energy production by 7% annually by the end of the century. Lower positive impacts are found in the tropical regions. In lowland rainforest areas, where inundation of a part of the forest is necessary, it has been noted that the reservoirs of power plants produce substantial amounts of methane . This is due to plant material in flooded areas decaying in an anaerobic environment and forming methane,

7708-788: The range-resolved infrared differential absorption lidar (DIAL). Greenhouse gases are measured from space such as by the Orbiting Carbon Observatory and through networks of ground stations such as the Integrated Carbon Observation System . The Annual Greenhouse Gas Index (AGGI) is defined by atmospheric scientists at NOAA as the ratio of total direct radiative forcing due to long-lived and well-mixed greenhouse gases for any year for which adequate global measurements exist, to that present in year 1990. These radiative forcing levels are relative to those present in year 1750 (i.e. prior to

7802-605: The same element , they have no asymmetry in the distribution of their electrical charges , and so are almost totally unaffected by infrared thermal radiation, with only an extremely minor effect from collision-induced absorption . A further 0.9% of the atmosphere is made up by argon (Ar), which is monatomic , and so completely transparent to thermal radiation. On the other hand, carbon dioxide (0.04%), methane , nitrous oxide and even less abundant trace gases account for less than 0.1% of Earth's atmosphere, but because their molecules contain atoms of different elements, there

7896-470: The same mass of carbon dioxide over a 20-year time frame. Since the 1980s, greenhouse gas forcing contributions (relative to year 1750) are also estimated with high accuracy using IPCC-recommended expressions derived from radiative transfer models . The concentration of a greenhouse gas is typically measured in parts per million (ppm) or parts per billion (ppb) by volume. A CO 2 concentration of 420 ppm means that 420 out of every million air molecules

7990-404: The soil, the oceans and other waters, or vegetation and other biological systems, reducing the excess to background concentrations. The average time taken to achieve this is the mean lifetime . This can be represented through the following formula, where the lifetime τ {\displaystyle \tau } of an atmospheric species X in a one- box model is the average time that

8084-521: The start of the industrial era ). 1990 is chosen because it is the baseline year for the Kyoto Protocol , and is the publication year of the first IPCC Scientific Assessment of Climate Change . As such, NOAA states that the AGGI "measures the commitment that (global) society has already made to living in a changing climate. It is based on the highest quality atmospheric observations from sites around

8178-418: The table. and Annex III of the 2021 IPCC WG1 Report (years) GWP over time up to year 2022 Year 1750 Year 1998 Year 2005 Year 2011 Year 2019 Mole fractions : μmol/mol = ppm = parts per million (10 ); nmol/mol = ppb = parts per billion (10 ); pmol/mol = ppt = parts per trillion (10 ). The IPCC states that "no single atmospheric lifetime can be given" for CO 2 . This

8272-424: The top-of-atmosphere, which causes additional warming, while negative forcing, like from sulfates forming in the atmosphere from sulfur dioxide , leads to cooling. Within the lower atmosphere, greenhouse gases exchange thermal radiation with the surface and limit radiative heat flow away from it, which reduces the overall rate of upward radiative heat transfer. The increased concentration of greenhouse gases

8366-424: The village of Stejaru in the commune of Pângărați. It is a high head type of power plant with reservoir and pressurized diversion (adduction gallery), balancing tower, penstocks, distributors, power plant, powerhouse, stilling basin and tailrace. Over the years, the power plant has benefited from various repair activities, sub-assembly replacements, automation equipment optimizations and equipment upgrades. The lake

8460-524: The world are hydroelectric power stations, with some hydroelectric facilities capable of generating more than double the installed capacities of the current largest nuclear power stations . Although no official definition exists for the capacity range of large hydroelectric power stations, facilities from over a few hundred megawatts are generally considered large hydroelectric facilities. Currently, only seven facilities over 10 GW ( 10,000 MW ) are in operation worldwide, see table below. Small hydro

8554-602: The world. It excludes water vapor because changes in its concentrations are calculated as a climate change feedback indirectly caused by changes in other greenhouse gases, as well as ozone, whose concentrations are only modified indirectly by various refrigerants that cause ozone depletion . Some short-lived gases (e.g. carbon monoxide , NOx ) and aerosols (e.g. mineral dust or black carbon ) are also excluded because of limited role and strong variation, along with minor refrigerants and other halogenated gases, which have been mass-produced in smaller quantities than those in

8648-539: The world. The classification of hydropower plants starts with two top-level categories: The classification of a plant as an SHP or LHP is primarily based on its nameplate capacity , the threshold varies by the country, but in any case a plant with the capacity of 50 MW or more is considered an LHP. As an example, for China, SHP power is below 25 MW, for India - below 15 MW, most of Europe - below 10 MW. The SHP and LHP categories are further subdivided into many subcategories that are not mutually exclusive. For example,

8742-408: The world. Its uncertainty is very low." The natural flows of carbon between the atmosphere, ocean, terrestrial ecosystems , and sediments are fairly balanced; so carbon levels would be roughly stable without human influence. Carbon dioxide is removed from the atmosphere primarily through photosynthesis and enters the terrestrial and oceanic biospheres. Carbon dioxide also dissolves directly from

8836-586: Was allowed to provide irrigation and power to citizens (in addition to aluminium power) after the war. In Suriname , the Brokopondo Reservoir was constructed to provide electricity for the Alcoa aluminium industry. New Zealand 's Manapouri Power Station was constructed to supply electricity to the aluminium smelter at Tiwai Point . Since hydroelectric dams do not use fuel, power generation does not produce carbon dioxide . While carbon dioxide

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